1. Field of the Invention
The present invention relates to detection of ink tank mounting positions within a recording apparatus and the status of the recording apparatus' mechanism used to determine the mounting positions.
2. Related Background Art
In recent years, in association with the spread of digital cameras, the number of applications in which a digital camera and a printer are directly connected, without the aid of a personal computer (PC), to print digital images has been increasing. In addition to printing directly from a digital camera, other methods of printing without the use of a PC that have been gaining in popularity include removing the storage medium (e.g., compact flash card, secure digital card, etc.) from a digital camera and connecting the storage medium directly to the printer.
In the case of printing using a PC, it is known to confirm the ink residual amount in an ink tank of a printer using the PC's display. The need to confirm ink residual amount in the case of printing without using a PC has been increasing. For example, if a user can preliminarily recognize the fact that ink residual amount in the ink tank is small, the user, for example, can exchange the ink tank for a new ink tank prior to starting printing, thus avoiding any problems (e.g., incomplete printing) that may occur during printing due to the lack of ink.
Hitherto, notifying a user of the condition of an ink tank using a display device such as an LED or the like has been known. In Japanese Patent Application Laid-Open No. H04-275156, two LEDs are provided for an ink tank integrally mounted with a recording head, where each of the LEDs is turned on in accordance with an ink residual amount of two stages.
To satisfy the requirement for higher picture quality, in addition to the conventional four color inks (black, yellow, magenta, cyan), various types of ink, such as light magenta and light cyan, whose concentration is low have been used. Further, the use of so-called particular color inks, such as red ink and blue ink, has been proposed. When these inks are used, seven or eight ink tanks corresponding to the colors are individually mounted in an inkjet printer. In this case, a mechanism is necessary to prevent the ink tank from being mounted at wrong positions. Japanese Patent Application Laid-Open No. 2001-253087 discloses that the engaged portions between a carriage and ink tanks have different shapes. This prevents the ink tanks from being improperly mounted.
In order to specify the mounting positions of the ink tanks, the engaged portions between the carriage and the ink tanks have different shapes, as described above. In this case, however, it is necessary to produce ink tanks that have different shapes corresponding to the colors and types of ink. This is disadvantageous in terms of production efficiency and cost.
As another method, it is conceivable to separately provide different circuit signal lines of circuits, which are formed by connecting electrical contacts of ink tanks and electrical contacts provided at the mounting positions of the ink tanks in a carriage of a main unit, corresponding to the mounting positions. For example, it is conceivable to respectively provide different signal lines corresponding to the mounting positions in order to read ink color information from the ink tanks, and to control lighting of LEDs. When the color information read from any of the ink tanks does not correspond to the mounting position, it is determined that the ink tank is mounted improperly.
Such a construction that the signal line is individually provided every ink tank or mounting position results in an increase in the number of signal lines. Particularly, as mentioned above, in the recent ink jet printers or the like, there is a tendency that the picture quality is improved by increasing the number of kinds of ink to be used. In such a printer, particularly, the increase in the number of signal lines becomes a factor of the increase in costs or the like. A construction such as bus connection of what is called a common signal line is effective in order to reduce the number of wirings. However, according to the construction such as bus connection merely using the common signal line, it will be obviously understood that the ink tank or its mounting position cannot be specified.
Accordingly, a position checking method is conceivable in which lighting of LEDs at mounting positions of a plurality of ink tanks is controlled by a common signal line, and in which the mounting positions of the ink tanks can be determined. However, the amount of emitted light varies among the LEDs, and therefore, the amount of light received by a light receiver provided in the printer also varies. For this reason, it is sometimes difficult to check the presence or absence of emitted light with reference to a threshold value depending on the amount of received light, and to thereby check the positions of the ink tanks. Although this problem can be solved by reducing the variation in the amount of emitted light, the cost is increased, for example, because there is a need to screen LEDs.
However, if the mounting position of the ink tank cannot be correctly specified due to the occurrence of a failure of the photosensitive device, deterioration of photosensitivity by ink mist, or the like, it is impossible to determine that such a problem has been caused by the erroneous mounting of the ink tank or by the failure of the main body. Thus, such a problem that the ink tank is unnecessarily exchanged occurs.